Lipolytic response of adipose tissue and metabolic adaptations to long periods of fasting in red tilapia (Oreochromis sp., Teleostei: Cichlidae)

ABSTRACT Adaptive changes of carbohydrate and lipid metabolism induced by 7, 15, 30, 60, 90, 150 and 200 days of fasting were investigated in red tilapia (Oreochromis sp.). Plasma glucose, lactate and free fatty acids (FFA) levels, liver and muscle glycogen and total lipid contents and rates of FFA release from mesenteric adipose tissue (MAT) were measured. Plasma glucose levels showed significant differences only after 90 days of fasting, when glycemia was 34% lower (50±5mg.dL-1) than fed fish values (74±1mg.dL-1), remaining relatively constant until 200 days of fasting. The content of liver glycogen ("15%) in fed tilapia fell 40% in 7 days of food deprivation. In 60, 90 and 150 days of fasting, plasma FFA levels increased 49%, 64% and 90%, respectively, compared to fed fish values. In agreement with the increase in plasma FFA, fasting induced a clear increase in lipolytic activity of MAT incubated in vitro. Addition of isobutylmethylxanthine (cAMP-phosphodiesterase inhibitor) and isoproterenol (non selective beta adrenergic agonist) to the incubation medium induced a reduction of lipolysis in fasted fish, differently to what was observed in mammal adipose tissue. This study allowed a physiological assessment of red tilapia response to starvation

In vivo assessment of cyto/genotoxic, antigenotoxic and antifungal potential of Costus spiralis (Jacq.) Roscoe leaves and stems

ABSTRACT Costus spiralis is a Brazilian native plant used in popular medicine, but the safety of this therapeutic use needs investigation. So, the aim of this study was to evaluate the cytogenotoxic and antigenotoxic effects of C. spiralis leaves or stems aqueous extracts on Allium cepa root cells. Moreover, a phytochemical screening and an antioxidant and antifungal activities evaluation were performed. C. spiralis aqueous extracts presented cytotoxicity, but no mutagenicity was observed. When the antigenotoxicity was evaluated, C. spiralis leaves aqueous extract presented preventive and modulatory effects on A. cepa root cells, reducing the sodium azide cytogenotoxic effects. In contrast, C. spiralis stems aqueous extract enhanced the sodium azide cytogenotoxicity in some conditions. The phytochemical screening revealed the presence of phenolic compounds in C. spiralis. When total phenolic content was determined, the leaves presented 73% more phenolic content than stems. Corroborating this data, C. spiralis leaves antioxidant potential was 30% higher than C. spiralis stems. However, these extracts did not present antifungal activity against Candida spp. In conclusion, empirical utilization of C. spiralis aqueous extracts should be avoided. Moreover, the cytotoxic effect of C. spiralis leaves and stems can play an important role in anticancer therapy and must be deeply studied